Please help me with these if u can!

Sandy is ordering bread rolls for her party, she wants 3/5 of the rolls to be whole wheat. what other factions can represent part of the rolls that will be whole wheat? shade the models to show your work.

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

How can you find the magnitude of a vector, v = < x, y > , where the horizontal change is x and the vertical change is y?